The invention relates to a method for disinfecting a microtome cryostat with                a) Introduction of a disinfection agent into the cryostat chamber        b) Action of the disinfection agent on the cryostat chamber        c) Removal of the disinfection agent by precipitation in a colder area and drainage away from there.        
The invention also relates to a device for disinfecting a microtome croyostat by a method of that type with a microtome, a cold generator, a facility for the provision and introduction of a disinfection agent into the cryostat chamber and a control.
Because microtomes are often used to section tissue specimens that are infected with germs, disinfection is a requirement for the protection of the operating personnel. The following proposals have been made for such disinfections:
One proposal for solving the problem in US 2002/0139124 A1 is to perform the disinfection with ozone. However, this has the disadvantage that ozone is very corrosive and damages surfaces by oxidation. A further disadvantage is that ozone residue is difficult to remove, is toxic, and is highly flammable, or can partially escape from the device during the disinfection phase, thus posing a hazard to operating personnel.
The brochure “AS 600 Cryotome” of the company ANGLIA SCIENTIFIC proposes another solution for decontamination using ultraviolet radiation. However, this has the disadvantage that the ultraviolet radiation does not penetrate into shaded regions. Moreover, there is no depth of penetration of the ultraviolet rays into section waste or specimen remnants, or into microscopically small depressions in metal surfaces. This method of decontamination is therefore unsatisfactory.
A method and a device of the type described in the introduction is proposed by DE 103 03 989 B4, wherein a vaporous disinfection agent is conveyed into a cryostat chamber that has previously been heated. After a disinfecting time, the disinfection agent is removed by the generation of a difference in temperature between the cryostat chamber and a cold generator, which causes the microtome, which preferably continues to be heated, to be dried and the entire disinfection agent is precipitated onto the cold generator which has been restarted. It is thawed and removed from there by reheating the cold generator. The cold generator is then restarted so that the cryostat chamber regains its operating temperature. This procedure was already considerably faster than drying out simply by leaving the cryostat open after disinfection until the cryostat chamber with microtome is dry. Nevertheless, it still takes at least two hours for the microtome to restart, this time period consisting of the defrosting and heating time, the provision and disinfecting time of the disinfection agent, and the time required to remove the disinfection agent, and for recooling. Therefore, disinfection can either only be performed at the end of a working day or, if a high risk of infection necessitates more frequent disinfection, a considerable restriction in the deployment of the microtome cryostat will result.
The object of this invention is therefore to provide a method and a device of the type stated in the introduction such that the microtome cryostat can be disinfected several times per day without prolonged interruption of operation.